1. Field of the Invention
The present invention relates to linearization of power amplifiers. In particular, the present invention relates to linearization of power amplifiers in a multi-path transmitter.
2. Discussion of the Related Art
To facilitate deployment and to reduce operating expense, small cells in a cellular communication system must be highly efficient (e.g., have a small form factor and be low-power). With high efficiency, the size, the weight and the cost of components, heat sinks, power supplies and enclosures can be reduced. For indoor use, Power over Ethernet (PoE) is another highly desirable technology that minimizes installation cost. Recent advances in adaptive, closed-loop RF linearization have made it possible to economically linearize RF power amplifiers, including power amplifiers that are Class A, Class AB or Doherty, even at the low power levels used in small cells. To linearize a power amplifier, a linearization circuit conditions the input signal by combining it with a pre-distortion signal, such that the output of the power amplifier bears a substantially linear relationship to the input signal.